Soon Sung Kwon

HbA1c for diagnosis and prognosis of gestational diabetes mellitus

AIMS HbA1c is a widely used marker in diagnosing type 2 diabetes mellitus (DM), but its clinical utility in diagnosing gestational diabetes mellitus (GDM) is not established. Here, we evaluated the clinical usefulness of HbA1c in diagnosing GDM and predicting the risk of future type 2 DM development among GDM patients. METHODS This retrospective, cross-sectional study included 321 subjects who underwent 100-g oral glucose tolerance tests (OGTT) during pregnancy. HbA1c and other variables were analyzed to evaluate their diagnostic performance for GDM. To evaluate the clinical usefulness of HbA1c in predicting future type 2 DM development, we classified GDM subjects who had more than 3 months of follow-up data into two subgroups: those who developed postpartum type 2 DM (PDM) and those who did not. RESULTS HbA1c was significantly higher in the GDM group than in the normal control group. With the 100-g OGTT as reference, HbA1c showed 91.3% sensitivity and 62% specificity at a cut-off value of 5.05% (32 mmol/mol) for GDM diagnosis. At a cut-off value of 5.25% (34 mmol/mol), sensitivity was 73.6% and specificity was 77.2%. HbA1c levels during pregnancy were higher in those with PDM than in those without PDM (5.91 [41 mmol/mol] vs. 5.44% [36 mmol/mol], p<0.001). The prognostic value of HbA1c for PDM was evaluated by ROC curve analysis, with sensitivity of 78.6% and specificity of 72.5% at a cut-off value of 5.55% (37 mmol/mol). CONCLUSIONS HbA1c showed high sensitivity with relatively low specificity for diagnosis of GDM in pregnant women and was a potential predictor of PDM. HbA1c may be able to be used as a simple and less invasive alternative screening test for OGTT in GDM patients.

Homeostasis model assessment of insulin resistance in a general adult population in Korea: additive association of sarcopenia and obesity with insulin resistance

Insulin resistance (IR) is a major factor associated with type 2 diabetes. Using homeostasis model assessment of insulin resistance (HOMA‐IR), we aimed to elucidate the factors associated with IR risk, especially the cumulative effect of obesity and sarcopenia on IR.

Efficacy of Stiripentol in Dravet Syndrome with or without SCN1A Mutations

Background and Purpose The aim of this study was to determine the effectiveness of stiripentol (STP) add-on therapy to valproate and clobazam in patients with Dravet syndrome (DS) according to the presence of mutations in the sodium channel alpha-1 subunit gene (SCN1A). Methods We performed direct sequencing to analyze SCN1A mutations in 32 patients with clinically confirmed with DS, and classified them into mutation (pathogenic or likely pathogenic) and nonmutation groups based on American College of Medical Genetics and Genomics guidelines. We compared the efficacy of STP in reducing the seizure frequency between the two groups. Results The 32 patients comprised 15 patients in the mutation group (with definite SCN1A mutations) and 17 patients in the nonmutation group with variants of unknown significance or benign variants. The clinical profile did not differ significantly between the mutation and nonmutation groups. The seizure frequency relative to baseline reduced by 72.53±23.00% (mean±SD) in the mutation group versus 50.58±40.14% in the nonmutation group (p=0.004). The efficacy of STP was better in DS patients with missense mutations that in those with truncation mutations, and was not favorable in patients with mutations at linkers between domains (DII–DIII), linkers between segments of domain I (DI S1–S2), or splice sites, although the small number of patients prevented statistical analyses. Conclusions The efficacy of STP was significantly better in DS patients with definite SCN1A mutations than in those without mutations.

Automated CH50 liposome-based immunoassay: consideration in dilution and validation of reference interval.

*Corresponding author: Hyon-Suk Kim, Department of Laboratory Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea, Phone: +82-2-2228-2443, Fax: +82-2-364-1583, E-mail: kimhs54@yuhs.ac Jihoon G. Yoon, Borae G. Park, Soon Sung Kwon and Jaewoo Song: Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea. http://orcid.org/0000-0001-9710-9253 (B.G. Park) Letter to the Editor

Evaluation of an automated urinary iodine measurement using AU5800 analyzer with AutoLab Iodine reagent.

*Corresponding author: Duck Jin Hong, Department of Laboratory Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea, Fax: +82-2-2057-8926, E-mail: dududuck@hanmail.net Soon Sung Kwon, Byungkwang Kim, Sung Won Hwang, Kwangwoo Kim and Seok Hoon Jeong: Department of Laboratory Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea Jeong-Ho Kim: Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea Letter to the Editor

Deletion of 20p13 and Duplication of 20p13p12.3 in a Patient with Delayed Speech and Development

Dear Editor, Few cases involving deletions and duplications of the short arm of chromosome 20 have been reported; these patients present various phenotypes, including developmental delays and dysmorphic features [1-10]. In the majority of cases, 20p deletions and duplications are accompanied by defects in other chromosomes [1-3]. Here, we report a patient with a complex partial deletion and duplication involving 20p only, identified by chromosomal microarray (CMA). A 3-year-old girl visited Severance hospital located in Shinchon, Seoul, in 2015 for evaluation of delayed speech and development. The patient had been managed for speech and developmental delays in our center for a year. There was no family history of delayed development, and her older sister and brother showed normal development. The patient was born at 34 weeks of gestation by cesarean section, and her birth weight was 3,840 g. Her growth parameters, weight, height, and head circumference were within normal ranges. Physical examination indicated mild craniofacial dysmorphisms, including a bulging head, prominent forehead, widely spaced eyes, wide nasal bridge, and a prominent lower jaw. She also exhibited pes plano valgus. Psychological assessment revealed psychomotor retardation with delayed social development. Direct sequencing of MECP2 revealed no pathogenic variant. Conventional G-banding chromosome analysis showed a duplication in 20p; however, the affected regions could not be designated accurately. Further CMA testing revealed a 928-kb deletion in 20p13 and a 6.6-Mb duplication of 20p13p12.3; the final karyotype was designated as arr 20p13 (61,661-1,043,325)×1, 20p13p12.3(1,045,639-7,604,026)×3. The patient’s speech development improved and normalized following two years of speech training. The genetic analysis in this study was conducted with the written informed consents from the parents of the patient. This study was exempted from approval by the institutional review board of the hospital (Fig. 1). Although various clinical features such as dysmorphic face, and language and developmental delay have been associated with partial 20p deletion and duplication, correlations between deletions, duplications, and phenotype are complicated by accompanying defects in other chromosomes. Deletions involving the short arm of chromosome 20 are rare. Most of these include the deletion of JAG1 located in 20p12.2, known to be related to Alagille syndrome, which affects the liver, heart, and other organs and manifests distinctive facial features [9]. Deletions of 20p13 excluding JAG1 are rarer and have been reported to be related to motor and speech development delays, varying degrees of mental retardation, various forms of epilepsy, and mild

Performance of Matrix-Assisted Laser Desorption Ionization Time-of-Fight Mass Spectrometry for Rapid Discrimination of Methicillin-Resistant Staphylococcus aureus (MRSA): First Report of a Relation Between Protein Peaks and MRSA spa Type

Dear Editor, Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is widely applied for the rapid identification of bacterial species [1]. However, an antimicrobial susceptibility test (AST) should be performed by using conventional methods following MALDI-TOF MS, and this delay represents a significant hurdle for the rapid adjustment of administered antimicrobial treatments. To overcome this limitation, many methods to improve MALDI-TOF MS for the production of rapid AST results have been proposed [2–4]. For example, carbapenemase-producing Enterobacteriaceae can be detected by analyzing the MALDI-TOF MS peaks of carbapenems and their metabolites [2, 3]. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important multidrug-resistant organism in hospital and community settings. To date, few studies have attempted to differentiate MRSA and methicillin-susceptible S. aureus (MSSA) using MALDI-TOF MS. Despite the subsequent identification of many MRSA-specific peaks, no indisputable evidence has been obtained for reliable markers for MRSA and MSSA discrimination [5–7]. Furthermore, no study has evaluated Korean S. aureus isolates to date. Therefore, we aimed to identify MRSA isolates in Korea using MALDI-TOF MS peak analysis, and evaluated the feasibility of employing this method in clinical microbiology laboratories. This study was approved by institutional review board of Yonsei university health system (Approval number 4-2017-0456) and informed consent was waived due to the retrospective manner of this study. We collected S. aureus isolated from the anterior nares of patients with atopic dermatitis from 2012 to 2013. Of 81 isolates, 47 were MSSA and 34 were MRSA as confirmed by the cefoxitin disc diffusion test according to the CLSI document M100-S25 [8]. All isolates were processed for protein extraction by using Microflex LT (Bruker Daltonics GmbH, Bremen, Germany) according to the manufacturer protocol. In Phase 1, peptide profiles were analyzed by using the QuickClassifier algorithm of ClinProTools 3.0 software (Bruker Daltonics GmbH). This model showed good sensitivity and specificity (Ta-